Health insurance for expat

Hi there,
My wife and I are moving to Tokyo in late July and I am a little confused about what the requirements are for health insurance.
My wife is covered by her employers but I am not. They want a ridiculous amount (US$590/month) to add me to her policy. I will have a dependent visa (i will try to get a part time job)
Thanks for reading and I look forward to some responses

Is your wife's employer a local Japanese entity, or are they sending her to their Japan office as an "expat" from their home country?

It depends on the insurance scheme they have, but that amount sounds like a full home country health insurance rather than a local one. Since you will have a "dependent" status, meaning a resident in Japan, you might consider signing up with the national health insurance scheme.

She has a new job with a Japanese institution, a two year contract.
So we don't know if we will be there for 2 years or multiples of.

The exact type of her "Japanese institution" would determine which health scheme you would fall under. For instance, is she were on the faculty of a private school, she'd fall under this plan:

http://www.shigakukyosai.jp/en/s_term/index.html

If she were working in a different sector, however, she'd have a different plan.

What type of employer will she have?

If you were not join her plan, you might be able to apply for insurance on your own through the National plan. You'd need to contact someone, give them an idea of your situation, in order to get an estimate of the cost.

Also, Tokyo is actually made up of various wards and cities, and there is not one uniform health insurance rate. Here's a page (in Japanese) showing some of the differences just for the Tokyo area:

http://www.kokuho-keisan.com/list/list.php?pref=13

If the spouse works and has a health plan from his/her company, is it compulsory for the other spouse (assuming zero income) to join it? Or the other spouse can go with the national health insurance?

If the spouse works and has a health plan from his/her company, is it compulsory for the other spouse (assuming zero income) to join it?

I don't think so. But it is recommended, because the spouse will be covered by the same benefits without additional cost (assuming income of under 1 million yen per year).

Or the other spouse can go with the national health insurance?

I think the spouse is free to go with national health insurance, but if he/she earns under around 1 million yen per year, he/she can join the partner's health insurance as a dependent and will be covered by the same plan at no additional cost.

Join the NHI scheme - takes a short amount of time to sign up when you do things like registering your address with your local city hall. For the first year it is very inexpensive because your income is zero in the previous year, and you still get good coverage (covered my root canal nicely).

maybe that amount comes with pension + health insurance ....if is only health insurance . is too expensive for family with dependant spouse and kids.

I don't think so. But it is recommended, because the spouse will be covered by the same benefits without additional cost (assuming income of under 1 million yen per year).

Thank you for the clarification Uji. I did not know there were no additional costs, I assumed it was like the national health plan, where even without any income a person still has to pay a basic amount.

The other plan they are offering is $950US a month has pension benefits.
I am thinking of just getting my own independent health insurance from my home country (aus) I can get it for about $300 AUD per month.
I just wasn't sure if it was 'compulsory' to have a local policy.

As far as I know, it is compulsory to join the local scheme, either on your own with the national health insurance, or through your or your family's employer scheme.

Even if it is not compulsory (it is if you are working AFAIK - legal requirement on me as an employer), the schemes work very well.
For example, one of my staff under the NHI and before they got their work visa had a medical event and two weeks in hospital after emergency surgery. Cost them about 100,000 yen as that was the piece not covered by insurance, but three hours in an operating theater and two weeks hospitalization would have been a couple of million yen.
With the health insurance they are currently under (required because they are working), they have also needed surgery for something (more expensive) and I think it's costing them around 30,000 yen/month for coverage (I probably have the numbers on my computer somewhere.)